Method and apparatus for the manufacture of dipped rubber goods



Patented Oct. 7, 1947 'UNITED STATE METHOD AND APPARATUS FOR lTHE MANU'-FACTURE OF DIPPED RUBBER GOODS yJohn M. Auzin, lWarwick, R. I.,assignorto 'Davol Rubber Company, a corporation of 4Island RhodeApplicationJuly'Z, 19475, Serial No. 602,873

y The present invention relates to the manu- `facture of rubberarticles, and has particular ref.-

`erence to the manufacture of pessaries and the like by dipping.

The principal object of theinvention is to provide a novel arrangementfor facilitating the frmation of a roll edge on a pessary or the li e. A

Another object of the invention is to provide a vnovel arrangement whichsimplifies the rolling of the edge around a resilient core.

With the above and other objects and advantageous features in view, theinventionconsists of a novel form and a novel procedure for `.obtaininga roll edge on a pessary or -the like in. a simple and effective manner,more fully disclosed in the detailed description following, inconjunction with the accompanying drawings.

In the drawings:

Fig. 1 is a front elevation of a pessary having a roll edge formed inaccordance with the invention;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a perspective View of the novel form for dipping, a resilient,coil spring being shown in position for forming the core; and

Fig. 4 is a vertical section through the mold, after dipping, with theroll edge partly formed.

The manufacture of pessaries and similar articles having roll or beadedges normally is accomplished by dipping a suitable form in natural orsynthetic rubber in solution, such as latex, to vprovide the body of thearticle and an elongated skirt, placing a resilient core such as a coilspring over the lower edge of the skirt, and then rolling up theresilient core in the skirt so as to embed the core in the rolled upmaterial and form a roll edge or bead. It has been found that a form ofuniform diameter, such as is commonly used, causes the tension of theresilient core to increase as the roll edge builds up, and that theskirt, if in moist condition, will slide up and buckle ahead of thespring coil unless the tension is released. It has also been found thatit is advantageous to form the roll edge when the skirt is in moistcondition, as the bond between the resilient core and the envelopingmaterial is firmer and a higher production results; whereas theformation of a roll edge after thorough drying of the rubber materialrequires time and additional handling, as well as reducing the strengthof the bond.

I have therefore found it advisable to provide a form which has theusual pessary shape, for example, at the dipping end, and which has a.

2 Claims. (Cl. IIS-47.5)

Y 22 tapered lead towards the dippingV end, this tapered lead increasingin diameter just below the usual pessary roll edge groove, so that theresilient core, which is initially slightly distended, rst graduallydecreases in diameter and then momentarily increases in diameter beforeentering the roll edge groove. The tapered lead facilitates the rollingprocess and. eliminates. sliding back of the skirt, andthe slightexpansion before the roll edge groove is reached equalizes the tensionin the core and smooths out the formed roll edges so that the roll edge,,when within the groove, is of uniform tension, and. is symmetrical andsmooth in shape, whereby the vfinished articles are uniform in shape,and. dry and cure without distortion.

Referring to the drawings, thepessary III includes a exible dome II anda roll edge I2 in which a resilient core I3, preferably a spiral wirecoil, is embedded. A special form I4, see Fig. 3, is used for dipping,the form having a dome top I5, a roll edge groove I6, and a body portionI'I. The body portion has a lower groove I8 in which the resilient coreis initially placed, and a tapered central portion I9 which is marked orscored, as indicated at 20, to disclose the dipping depth, this depthbeing about 1% inches for a 75 mm. pessary and about 11A inches for asmaller pessary. The tapered central portion I9 is initially of greaterdiameter than the roll edge groove, as indicated at 2l, then tapers downalmost to the diameter of the roll edge groove, as indicated at 22, thenabruptly enlarges, as indicated at 23 when closely adjacent the rolledge groove IB, to form a slight circumferential hump or ridge 24. Theinitial out taper should be about 1/2 inch, and the slope-in should beabout 2% inches.

The form I4 is first dipped in latex or other rubber solution t0 theline 20, to obtain an elastic layer 25 having a depending skirt 25a, seeFig. 4, the thickness of layer found suitable being about .012 inch. Thecoil spring I3 is already in position in the groove I8, see Fig. 3, andis readily moved out of the groove and over the tapered central positionI9, as the taper causes it to smoothly roll down, this smooth rollingdown being facilitated and aided by the natural lcontraction of the coilspring, which is initially under slight tension when it passes over theenlarged region 2l. As the coil spring advances, aided by itscontraction, it engages the lower edge of the skirt 25a, which rolls upalso as shown in Fig. 4, until the reduced diameter region 22 isreached, this region being preferably of slightly l()` hump thus servesto uniformly distribute the lcoilV spring and the rolled up skirl'I s othat the roll edgegr;l

or bead which seats Within thegroove `IE is uni-:'1- 'l Yform inV sizeand is uniform in tension.

manufacture is completed byfdrying'andicuring; since the roll edge coreis free when in the form' groove it becomes under adjusting tension whenthe pessary is cured. Y yThe novel method, by y thus produces auniformly satisfactory'product',

- vas the resilient core'is first stretched, then its tension isreleased to becomeequalized, and the formed roll edge is sharplymomentarily stretched too'btain a :close and uniformjoin between therolled'up skirt material andthe resilient core :partsl Althougha woodform issuitable, a por- "celainform may be used, 'suitably markedk to[show Y the dipping depth.

" vAlthough I have described a VSpecific form and "aspeci'prccedure'suitable for'the manufacture Thel .t

using the novel form,..

4 roll edge .containing a resilient core, comprising the steps ofdipping a generally cylindrical form in rubber solution to deposit alayer thereon having a skirt, positioning a resilient circular coreunder tension over the edge ofthe skirt to Ibecome emfbedded in theskirt material, and forming albead by rolling the skirt edge andtheresilient core over the deposited layer, lfirst gradually releasing thetension of the core 'during' the rolling operation, then momentarilysharply increasing the core tension, and finally reducingv the .coretension4 at the completion of the rolling'. Y operation. L

2. A generally, cylindrical form for dipping" -irufbberand. rubbermaterial articles having a.

roll edge or bead, comprising an upper dome end shaped to conform to thearticle, the body of .the form being Vreduced in diameter to provide anarrow annular groove below the dome end,V then 'being increased indiameter and again reduced in diameter to'provide a narrow humpv just:below the groove, and thenbeinggradually increased to a larger diameterthan thediameter Y of the groove to provide an" elongated ski'rtjdifp-goffroll edge or beaded 'pessaries it is obvious that lotherjarticles ofrubber or the like having 1ro-ll edges orjbeads maybe made, ftheforms'lbeing vdesigned tof correslond to the size and shape of fthedesired article.

u A1..11'he method of forming-anwarticlehaving "a 'terminal annulargroove at ping portion, the Yelongated portionlhavinga" its lower-end.:"7* JOHN AUzI1\r.-f REFERENCES CITED The'followingreferences are ofrecordrin'the lle'of this patent: V

UNITED STATES PATENTS i

